Five years ago he doubled the rows of boulders to make the sign more readable.
This year, helping muster for docking on the family farm, he noticed the sign was barely visible. Boulders had sunk into the ground, and grass had grown up and obscured them.
About a month ago he got to work with a brushcutter, carted more boulders up in a backpack, dug them in and painted them. To see the effect he had to climb down the hill and drive up the hillside opposite.
"That was a bit of a mission."
The sign is a lot more visible now, and he's proud of it.
"It certainly is an iconic thing for the region."
Back in 1986, Mark Wickham was asked what he wanted to do when he grew up.
The Chronicle recorded that it would be a toss-up between farming and tourism.
Sure enough, these days he's helping on the farm and also has a tourism business, Whanganui Scenic Experience Jet.